1. Field of the Invention
This invention pertaining to the field of biotechnology relates more specifically to a process for producing novel filtration membranes that are useful for the purpose of simultaneously separating and removing proteins and nonionic substances in solution.
2. Prior Art
Several types of beaded resinous affinity adsorbents are commercially available for use in the analysis or separation/purification of proteins. When beaded resinous adsorbents are packed in a column, a substantial pressure loss occurs upon passage of a feed solution because the bead diameter is adjusted to approximately 10 .mu.m with a view to accelerating the diffusion of proteins into the resin. This is a serious drawback when affinity beads are to be used in preparative chromatography, or chromatography on an industrial scale.
As an alternative, bioaffinity membranes are being under review based on the idea that proteins can be brought more advantageously into the vicinity of affinity ligands by convention rather than by diffusion. However, even this approach is unable to solve the aforementioned problem of beaded affinity adsorbents completely since affinity ligands attached to the membrane will constrict fine pores in it, thereby reducing its water permeability. In addition, no technique has been available by which affinity ligands capable of selectively capturing a group of specified proteins can be introduced in filtration membranes formed of polyolefins and other general-purpose polymers.